subject: Mineral vs Synthetic and the oil filter [print this page] Switching between mineral and synthetic oils If you are already using synthetics never downgrade to mineral as your engine might not be able to cope with the degradation (wear tolerance) in lubrication.
If you've already using mineral, don't switch to synthetic without first flushing the engine. Synthetic oils have been known to dislodge the baked-on deposits from mineral oils and leave them floating around your engine. Moreover, mineral-oil-soaked gaskets and seals of older model car have been known to leak when exposed to synthetic oils, use semi synthetic oil first before the final switch.
For long term sealing purposes and best performance, choose synthetics and never change your oil type. Switching to thinner synthetic oil (OW) provide less viscous drag which can gibe more horsepower and better fuel economy, however the may cause piston rings to leak and in some rare cases, piston slap or crank vibration.
Oil filters The oil filter is a strainer that filters out the solid particles of dirt and metal that are picked up in the circulating motor oil. Most oil filters are called full-flow' filters because they sit in the normal flow (in-line) of the oil through the engine. Therefore, the designed do not restrict oil flow around the circuit. They are normally effective at stopping the larger particles of around 20 micron in size which largely contributes to abrasive wear. The smallest contaminants are about 10-20 microns that would pass right through the oil filter and back out into circulation. Particulates too small to be filtered relies on the detergents and dispersants in the oil to hold then in suspension until it is changed. If the detergents and dispersants wear out, sludge and varnish will coat the internal surfaces of an engine. That is why you should change your oil filter at the recommended oil change intervals.
When the filter becomes clogged, a bypass valve allows these contaminants to continue circulating with the oil in the engine, damaging engine parts and creating sludge. It is aloes essential to prevent abrasive particles from entering the engine via the air intake. Most petrol driven engine pump about 10,000 liters of air for every liter of fuel consumed, and all with all that air, they suck in plenty of dirt. A good ail filter will sop everything bigger than a micron in diameter everything else just float around harmlessly in the oil.
Performance oil filters They usually incorporate an anti-drain back valve which reduces cold star wear. Also, the bypass valve flow rates and the particles pass through size have been effective filtering and good flow with low pressure drop. The performance filter also has a thicker shell and better crimping than the typical stock filter so it is less likely to blow off , if for instance, the bypass valve sticks or the oil is thick on a cold day. Some enthusiasts fit a aftermarket metal rings fitted around the oil filter manufactured as heat sinks to cool down the oil filter. There are no technical reports on the effectiveness of this as I understand. Another tweak is the use of magnetic drain plugs underneath the oil pan. This is said to attract minute particles of the metal that is circulating in the oil to be captured on the drain plug so that in the next oil change they can be easily removed. Users beware as they are usually made of aluminum and the threads are known to be easily damage when they are regularly wrenched in and out of the oil pan especially when excessive torque is applied. When the threads wear, the would leak engine oil.
Modern engines are said to have an increased lifespan, firstly due to the engine management systems that are not affected with rich cold start mixtures, thereby reducing oil dilution. Second, the switch to un-leaded petrol has also helped to eliminate corrosive acids in the crankcase. Finally, improved motor oils especially synthetics with better additives helps keep engines relatively clean hence prolonging wear and tear.
Good synthetics and regular oil changes becomes necessary if you push your engine hard. When running in new engines, use mineral based oils before switching to synthetics.
